1. Technical Field
This invention relates generally to a workpiece retention assembly and, more particularly, to a method and apparatus for supporting and positioning a workpiece.
2. Discussion
To use an inspection system to measure a workpiece it is highly beneficial and, for the most part, a requirement that the workpiece being inspected is accurately positioned and securely maintained in that position.
The conventional workpiece holder for use with an inspection system generally uses a single type of device positioned along a variety of locations on the workpiece. Moreover, the positioning devices are usually specially made for a specific workpiece and can not be used for other workpieces. In other words, conventional workpiece positioning and holding devices lack universality in that a single set up positioning device can not be used for workpieces having varied shapes and sizes. U.S. Pat. No. 4,641,819 to Poland discloses a jig assembly for holding a variety of workpieces for assembly or machining processes. Individual workpiece positioners are permanently attached to a base portion and a matrix configuration. Each positioner can be raised or lowered, and can reach points within a certain range by rotating a tip around 3 differing axis A, B and C. It appears that the workpiece rests on a supporting ledge adjacent the tip. One draw back of this workpiece holder is that it is not truly universally adjustable. As one axis is adjusted the other two are necessarily effected.
U.S. Pat. No. 3,681,834 to Seidensaden discloses a fixing and tensioning system for workpieces to be mechanically processed. A template is used over a platform having a uniform rectangular grid. The template indicates positions for modular units to support different workpieces. The modular units do not appear to be adjustable such that the fixing and tensioning system is truly universal.
British Patent No. 764,351 discloses a jig assembly for supporting motor vehicle body shells of differing sizes. A series of location units are arranged on the platform having a number of places for securing the units. The units can be moved to other locations on the platform to support other size vehicle frames. It does not appear however that the location units themselves are adjustable.
This invention eliminates the above described problems as well as many others. Up until now a universal workpiece measuring fixture for positioning and supporting a workpiece in a specific location was not known. This invention enables the operator to easily change from one workpiece to another using the same set of measuring fixtures. This invention also allows the operator to set the measuring fixture to support the workpiece at various desired angles.